Aerogels as Adsorbents: Mitigating the Environmental Impact of Oil Spills

Aerogels are highly porous, versatile materials with applications in many areas, including insulation, catalytic converters, and window inserts. Recently, aerogels have been employed as adsorbents for oil spills. With the increase in the use of fossil fuels over the last couple of decades, oil spills happen more frequently. Studies have estimated that over 100 million gallons of crude oil spill every year over the ocean water.¹ In this study, the adsorption capacity of hydrophobic silica aerogels and xerogels was investigated. Using a precursor solution that is 50% MTMS (methyltrimethoxysilane) makes a highly hydrophobic wet gel: a solid porous matrix in which the pores are filled with methanol and water. Processing the gels to remove the solvent by rapid supercritical extraction results in an aerogel; drying the gels under ambient conditions results in a less-porous xerogel. The aerogels have a density of 0.068 mg/mL and xerogels of 0.83 mg/mL.² The samples are weighed before and after they are added to an oil pool. Then, the absorption of oil is calculated in mg/g. Experiments have shown that the aerogel samples can absorb up to almost 900% their weight and the xerogels only about 50% of their weight. Both materials were characterized using infrared spectroscopy. This presentation will focus on the analysis of aerogels as oil adsorbents and how they compare to xerogels.

1. Bidgoli, H.; Mortazavi, Y.; Khodadadi, A. A. A functionalized nano-structured cellulosic sorbent aerogel for oil spill cleanup: Synthesis and characterization. J. Hazard. Mater. 2019, 366, 229-239 DOI:10.1016/j.jhazmat.2018.11.084.
2. Anderson, A. M.; Carroll, M. K.; Green, E. C.; Melville, J. T.; Bono, M. S. Hydrophobic silica aerogels prepared via rapid supercritical extraction. J Sol-Gel Sci Technol 2009, 53, 199.